• Pesticides help control weeds to maximize crop yield.working farm image by Jorge Moro from Fotolia.com
  
  Herbicides are chemically designed to kill off unwanted weeds that may harm agricultural crops or consume their resources. While some non-selective herbicides kill all plant life, more selective herbicides target specific weeds while not harming food products. Yellow, or dinitroaniline, herbicides are foundational herbicides for weed control that kill weeds before they emerge, and they are popularly used for peanut crops among many others.
  
  

Treflan

• The active ingredient in Treflan is trifluralin, which is also used in several generic brands. Treflan is available in liquid and granular form. It is used for both agricultural crops and flower beds. Dow AgroSciences reminds users, however, that Treflan does not affect weeds already established. After applying Treflan to the soil, users must then till the ground to mix the soil and herbicide at least two inches below. According to GeoFlow.com, "Treflan has established an outstanding record as an herbicide with an extremely low risk of reaching water supplies or leaching to groundwater when used according to label directions."
  
  

Prowl

• BASF Chemical Company designed Prowl as a water-based herbicide with the active ingredient pendimethalin. According to the BASF website, Prowl has no odor, does not stain and performs better in high surface areas; it is registered for more than 90 crops, including cotton, garlic, potatoes, tobacco and fruit trees. Because it comes in liquid form, users spray the herbicide and then water rather than physically incorporate granules into the ground. According to Larry J. Smith and Alan G. Dexter of the Sugarbeet Research and Education Board, however, Prowl and other yellow herbicides have been shown to remain in the soil through the growing season into the next year. This carryover may adversely affect the crops' yield the following season.
  
  

Sonalan

• Sonalan targets annual grasses and broadleaf weeds, and according to the Dow AgroSciences website, it may be used for "Canola, crambe, dry beans, dry peas, peanuts, safflower, soybeans and sunflowers." Sonalan should be applied no earlier than three weeks before planting. It too is available in both granular and liquid form. North Dakota State University's Extension Service notes that "Sonalan has less soil residue than trifluralin but is more active at comparable rates than trifluralin." Sonalan's label describes application instructions and duration. Similar to Prowl, Sonalan and Treflan will last into the next growing season; the potential effects should be considered before application.